Compound engine.



H. BOLTHOFP.

OOMPOUND ENGINE.

` APPLIGATION FILED mm1, 1910.

Patented Aug. 1, 1911.

. 4 SHBBTEPSHBET 1.

MUM WRAP C0., WA'SHINGTON. D. C.

H.'BOLTHO1EF.

GOMPOUND ENGINE.

1m f Patented Aug. 1,1911.

4 SHEETS-SHEET z Illlll H. BOLTHOPF.

GOMPOUND ENGINE.

APPLIOATION FILED mm1, 1910.

Patented Aug. 1, 1911.

4 SHEETS-SHEET 3.

' H. BOLTHOPP.

GOMPOUND ENGINE.

APPLICATION FILED JUNE 1, 1910.

Patented Aug. 1, 1911.

4 SHEETS-SHEET 4.

Witwe/oom Y COMPOUND ENGINE.

To all whom t may concern.'

Be it known that HENRY BOLTHOFF, a citizen of the United States,residing in the city and county of Denver and State of Colorado, haveinvented certain new and useful Improvements in Compound Engines; and ldo declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to the letters and figures of referencemarked thereon, which form a part of this specification.

My invention relates to improvements in compound engines, my objectbeing to provide a simple and ellicient engine of this type which shallbe so constructed that live steam or motive fluid may, if desired, befed to the low pressure cylinder simultaneously with the exhaust steamor fluid from the high pressure cylinder.

Furthermore, my improved construction is so arranged that both cylindersare in alinement, the pistons working therein being mounted on the samerod, the arrangement being such that the live steam in the high-pressurecylinder only acts on the piston to drive the latter in one direction,while the movement of the piston rod in the opposite direction isaccomplished through the agency of the exhaust steam in the low pressurecylinder, either alone or in combination with live steam admittedthrough a bypass which may if desired be placed in communication withthe low pressure cylinder simultaneously with the placing of the latterin communication with the exhaust from the high-pressure cylinder.

Having briefly outlined my improved construction, I will proceed todescribe the same in detail, reference being made to the accompanyingdrawing, in which is illustrated an embodiment thereof.

In this drawing: Figure 1 is a side View of my improved engine, shownpart-ly in section and partly in elevation. Fig. 2 is a horizontalsection taken on the line 2-2, Fig. 1, looking downwardly, the partsbeing shown on a larger scale. Fig. 3 is a sectional view of the steamchest similar to Fig. 2, but showing the slide valve in a differentrelative position. Fig. l is a similar view showing the slide valve instill another position. Fig. 5 is a vertical cross section taken on theline 5 5, Fig. et. Figs. 6, 7

Specification of Letters Patent.

Application filed .Tune 1, 1910.

Patented Aug. 1, 1911.

Serial No. 564,442.

and 8 are an end elevation, plan view and underneath view, respectively,of the slide valve shown in detail. Fig. 9 is a section taken throughthe steam chest on the line 9-9, Figs. 10 and 11. Fig. 1() is a sectiontaken on the line 10-10, Fig. 9. Fig. 11 is a side view of the steamchest with the detachable plate removed. This would be a View looking inthe direction of arrow 11, Fig. 10.

The same reference characters indicate the same parts in all the views.

Let the numeral 5 designate the highpressure cylinder and 6 thelow-pressure cylinder, the two cylinders having their axes in alinement.rI he high-pressure or smaller cylinder is provided with an exterior-lyprojecting flange 7 formed on the cylinder 5, and secured to the flangeS on the cylinder 6 by means of screws 9 or other suitable fasteningdevices. The shell of the cylinder 6 overlaps and partly incloses thatof the cylinder 5, leaving an annular space 10 between the overlappingportions of the two cylinders, the latter being spaced within. thisannular chamber by means of lugs 12 .formed on the shell of the smallercylinder. The annular space 10 is in communication with the chamber 13of the cylinder 6 and also in communication with an exhaust port 14C anda drain port 15. The chamber 13 of the cylinder 6 is in communicationwith the chamber 16 of the cylinder 5, the space between the pistons ofthese two cylinders being always in communication with the exhaust port14. The piston rod 17, is connected with a cross head 18, the latteractuating a pitinan 19 connected with the engine shaft 2O in the usualor any suitable manner. The piston rod 17 passes through a stuffing box21 with which the head 22 of the lowpressure cylinder is equipped.Nithin the cylinder 6, the rod 17 is connected to a piston 23 which fitsclosely within its chamber 13 and is secured to said rod by means of ashoulder Q4 on one side and a nut 25 on the other side. Beyond thepiston 23, the piston rod is extended, being somewhat reduced in size,as indicated at 26. The forward extremity of the piston rod is connectedto a piston 27 which fits closely within the chamber 16 of the cylinder5. When the engine is in operation, the live steam entering the cylinder5 forward of the piston, moves the latter toward the rear, while theexhaust steam from the cylinder 5 enters the chainber of the cylinder 6in the rear of the piston 23 and drives the same forwardly, either aloneor in conjunction with motive fluid, simultaneously admitted from thesteam chest, as hereinafter more fully explained.

Let the numeral 23 designate the steam chest, having a stuffing box 29at one extremity, through which a stem 30 passes, the inner extremity ofthe stem being connected with a slide 3l for controlling the ports 32,33 and 34, formed in the bottom of the steam chest or the side locateddirectly opposite the plate 35. In the special construction shown in thedrawing, the steam chest is mounted on one side of the shell of thecylinder 6. The shell of the cylinder forms one of the walls of thesteam chest, and the slide valve is reciprocated thereon. The port 32connnunicates with a passage 36 leading from the steam chest to theforward extremity of the cylinder 5; while the port communicates with apassage 37 leading from the steam chest to the rear extremity of thecylinder 6. The port 34 is the exhaust port and leads to the annularspace between the two cylinders. The ports 32 and 33, while they havethe same volume as the passages with which they connect, are flattenedout or made narrower in order that the opening or closing of the saidports by the action of the slide valve may be accomplished more quicklyor by a less movement of the valve, than were the ports wider. This isbelieved to be an advantage in a construction of this character', sincethe more quickly the ports are thrown wide open orY completely' closed,where the necessity for opening and closing exists, the more positivewill be the results obtained.

Tn order that some live steam may be admitted to the cylinder 6 in therear of the piston, simultaneously with the admission of the exhaustfrom the cylinder 5, to effect the proper degree of pressure in thelarger cylinder, T have provided the steam chest with a sort of by-pass38, one extremity 39 of which is always open to the steam chest, and theslide valve is provided with an extension 40 having a recess 41 incommunication with the chamber 42 of the valve. As heretofore stated,the extremity 39 of this by-pass is always open or in communication withthe steam of the chest, while its opposite extremity 43 is so locatedthat when the slide valve is in such position (see Fig. 2) that itschamber 42 is in communication with both ports 32 and 33, the recess 41is in communication with the port 43 of the bypass, thusallowing thesteam from the chest to mingle with the exhaust steam from the cylinder5 and pass through to the cylinder 6 in the rear of its piston 23. Thisby-pass 38 may, if desired, be closed against the passage of live steamthrough the instrumentality of a valve screw 44 which is threaded intothe top of the steam chest and capable of suflicient movement to eitheropen or close the by-pass which the valve screw is arranged to intersectand completely or partially close, as may be desired, for the purpose ofregulating the passage of the live motive fluid to the chamber of thecylinder.

)When the engine is in use, the steam or live motive fluid enters thesteam chest through a pipe 45, and if we assume that the slide valve isin the position shown in Fig. 4, that is to say, whereby the port 32 ofthe passage 36 is uncovered or placed in communication with the steam orlive fluid, the said fluid passes to the forward extremity of thecylinder 5 and acting upon the piston 27 drives the latter rearwardly.This live-steam continues to act upon the said piston unt-il it hasreached any desired position in its rearward travel. The action of theslide valve may be arranged to cut olf the live steam from the cylinder5 at any desired point.

Assuming now that the piston 27 has reached a point in its rearwardtravel suliiciently advanced to require that the live steam be cut offfrom the cylinder 5, the slide valve will move toward the right (seeFig. 3) sufficiently to cover t-he port 32 and it may be assumed thatthis port remains covered to allow the live steam to complete therearward stroke of the piston 27 by expansion, after which the continuedmovement of the slide valve toward the right, (see Fig. 2), places thetwo ports 32 and 33 in communication through the chamber 42 of the slidevalve, and the exhaust from the cylinder 5 forward of the piston 2.7flows through the passage 36, slide valve chamber 42 and the passage 37entering the chamber 6 in the rear of the piston 23. At the same time,the recess 40 of the slide valve registering with the port 43 of theby-pass 48 (see Figs. 9 and l0), and the live fluid flows through saidby-pass into the recess 40, and thence into the chamber 42 of the slidevalve, passing thence with the exhaust fluid through the passage 37 tothe cylinder 6 in the rear of the piston 23.. As the piston 23 is ofgreater area than the piston 27, the fluid acting on the piston 23 willmove both pistons forwardly, and force the motive fluid from forward ofthe piston 27, through passages 36 and 37, to the rear of the piston 23,and when the forward stroke is completed, the slide valve will beshifted toward the left (see Fig. 4) sufficiently to cause the chamber42 of the slide valve to register with the two ports 33 and 34, thelatter being the exhaust port, whereby the motive fluid in the rear ofthe piston 23 is allowed to exhaust through the passage 37, the chamberof the slide valve and the exhaust port of the annular space 10 betweenthe cylinders 5 and 6, and thence through the exhaust port 14. At thesame time the port 32 is uncovered and the live fluid flows from thevalve chest through the passage 36 to the cylinder 5 forward of thepiston 27, and the latter, together with the piston 23 and the stem 17,are driven again toward the rear and the operation heretofore describedis repeated. The live motive fluid introduced to the rear of the piston23 serves to increase the efficiency of the propelling power of theengine, due to the additional pressure on the piston 23 afforded by thelive motive fluid. rl`his live motive iiuid compensates for any leakageor condensation of the fluid primarily introduced forward of the piston27.

A suitable governor mechanism B constructed to be operated by the enginein any suitable manner, is provided for controlling or regulating theexhaust port 14, whereby when the speed of the engine is accelerated theexhaust port 14, is regulate-d to retard the exit of the exhaust frombetween the two pistons 23 and 27, thus causing the same to be coniinedbetween the two pistons and form a fluid cushion to be acted upon by theforward travel of the larger piston to retard the speed of the engine.As the cylinder 5 is smaller in area than the cylinder 6, only a portionof the fluid will follow the lpiston 27 into the cylinder 5, while theremainder of the fluid will be compressed in the annular space 10 andthe cylinder 6 to form a fluid cushion for the piston 23.

it will be understood that if it is not desired to utilize the livemotive fluid in conjunction with the exhaust in the low pressurecylinder, the valve screw 44 may be adjusted to close the by-pass, inwhich event when the exhaust fluid from the high pressure cylinder willbe utilized in the low pressure cylinder.

As heretofore explained, the efliciency of the operation of the enginewhen the fluid is acting on the piston of the low pressure cylinder,depends upon the difference in area between the faces of the two pistons23 and 27.

Having thus described my invention, what i claim is:

1. 1n an engine, the combination of two cylinders, of unequal diameter,arranged in alinement and in communication with each other, pistonslitted in the respective cylinder members, a common rod upon which bothpistons are mounted, a motive fluid chest and slide valve mechanism, thechest and cylinders having ports and passages larger extremity of eachcylinder, and another passage controlled by the slide valve for allowingmotive iiuid to pass between the two pistons from the larger cylinder,the exhaust taking place from between the two pistons, and meansgoverned by the speed of the engine for controlling the exhaust frombetween the two pistons.

2. In an engine, the combination of two cylinders of unequal diameter,arranged in alinement and in communication with each other, pistonsfitted in the respective cylinder members, a common rod upon which bothpistons are mounted, a motive iiuid chest and slide valve mechanism, thechest and cylinders having ports and passages for delivering live motivefluid to the forward extremity of the smaller cylinder and allowing itto pass to the rear extremity of the larger or low pressure cylinder,the chest also having a passage controlled by the valve mechanism forsimultaneously intro ducing live motive fluid with the motive iiuidpassing into the larger cylinder, and another passage controlled by theslide valve for allowing the motive fluid to pass between the pistonsfrom the other cylinder, the exhaust to the atmosphere taking place frombetween the two pistons, and means governed by the speed of the enginefor controlling the exhaust.

3. A compound engine, comprising high and low pressure cylinder membersin axial alinement and in communication with each other, pistons fittedin the respective cylinders, the exhaust to the atmosphere taking placefrom between the two pistons, and means governed by the speed of theengine for controlling the exhaust from between the two pistons, a rodupon which both the pistons are mounted, the pistons being so arrangedthat they simultaneously occupy corresponding positions in the twocylinder members, a motive fluid chest and slide valve mechanismtherein, the chest and cylinders having ports and passages controlled bythe slide valve mechanism, for admitting live motive fluid into theforward extremity of the high pressure cylinder and simultaneouslyexhausting fluid from the lowpressure cylinder, between the pistons, andfor conducting the exhaust from the forward extremity of the highpressure cylinder to the rear extremity of the low pressure cylinder,substantially as described.

4. In a motive Huid actuated engine, the combination of two cylindermembers of different diameters arranged in axial alinement, the rearextremity of one cylinder being in communication with the forwardextremity of the other cylinder, pistons fitted in the respectivecylinders, a rod upon which both pistons are mounted, a motive fluidchest having ports in communication with passages leading to the forwardextremity of one cylinder and to the rear extremity of the othercylinder, and a third port for exhaust purposes, communicating with apassage leading to the chamber of the cylinders between the two pistons,and a slide valve located in the motive iuid chest and operable touncover the port in communication with the passage leading to theforward extremity of one cylinder, at the same time that the portcommunicating with the rear extremity of the other cylinder is placed incommunication with the exhaust port through the slide valve chamber, theslide valve being also operable to close the exhaust port simultaneouslywith the placing of the other two ports in communication with each otherthrough the slide valve chamber to allow the exhaust to pass from theforward extremity of the high pressure cylinder to the rear extremity ofthe low pressure cylinder, the exhaust taking place to the atmospherefrom between the two pistons, and means governed by the speed of theengine for controlling the exhaust from between the pistons.

5. A compound engine comprising a hivhpressure cylinder, a low pressurecylincer, the rear extremity of one cylinder being in communication withthe forward extremity of the other cylinder and also constantly incommunication with the exhaust, a steam chest having a port incommunication with the forward extremity of the high pressure cylinder,another port in communication with the rear extremity of the lowpressure cylinder, a third port for exhaust purposes, a by-pass 4havingtwo ports, and a slide valve adapted to be manipulated to open the portcommunicating with the forward extremities of the high pressure cylindersimultaneously with the placing of the low pressure cylinder port incommunication with the exhaust port through the slide valve chamber, theslide valve also being operable to place the high pressure cylinderport, the low pressure cylinder port and one port of the by-pass incommunication with one another through the chamber of the slide valve,simultaneously with the closing of the exhaust port, the exhaust portbeing in communication with the interior of the two cylinders, betweenthe two pistons, and means governed by the speed of the engine forcontrolling the exhaust from between the two pistons.

In testimony whereof I afIix my signature in presence of two witnesses.

HENRY BOLTHOFF.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

